Progress!
I had these options set for experimentation:
$conf['server']['change_server'] = true;
$conf['server']['change_port'] = true;
$conf['server']['change_protocol'] = true;
Simply reverting to the default values of false AND setting 'protocol' =>
'imap' allows
me to login.
An observation:
First login displays a proper mailbox and all option buttons:
INBOX
Compose
Folders
Options
Search
Help
Addressbook
Logout
If I logout and login in again, I get a garbled screen with just Options
and Logout buttons.
If I refresh the page I get:
Not Found
The requested URL /horde/http://hostname/horde/login.php was not found on
this server.